Protochmeistry. The Program of a Methodical Foundation of Chemistry. "Protochemistry" — in analogy to protophysics — is sketched as the program of a methodical foundation of chemistry. "Foundation" means to reconstruct the methods (both linguistic and poietic) which lead from the prescientific every-day-practice of mastering properties of substances to scientific theories of modern chemistry. Four types of chemical terms are distinguished, depending on different methods of definition and different areas of reference. Consequences of the program if realized are pointed out.